TITLE Generic presynaptic button
 
COMMENT
Derived from The NEURON Book, Ch 9. Used to represent a basic presynapse. 
ENDCOMMENT
 
UNITS {: See lib/nrnunits.lib for default system values
        (mA) = (milliamp)
				(nA) = (nanoamp)
        (mV) = (millivolt)
}
 
: A shunt current
NEURON {
POINT_PROCESS PreSyn
NONSPECIFIC_CURRENT i
RANGE i, e, r
}

PARAMETER {
r = 1 (gigaohm) < 1e-9, 1e9 >
e = 0 (mV)
}

ASSIGNED {
i (nA)
v (mV)
}

BREAKPOINT { i = (0.001)*(v - e)/r }